1. Field of the Invention
The present invention relates to an apparatus and a method for transporting Intelligent Network signaling messages using an open system protocol, such as the Transmission Control Protocol/Internet Protocol.
2. Description of Prior Art
The emergence of Intelligent Network (IN) technology has resulted in an increasing number of centralized communication services (IN services) such as portable phone numbers, freephone (i.e., #800 Service), televoting, and credit-card calling. Generally, a network operator creates an IN by providing a centralized on-line database to an existing telecommunications network. By providing supplementary service information in centralized databases, instead of at local exchanges, new services may be rapidly offered to all network subscribers, not just to those subscribers connected to certain local exchanges.
Using #800 Service as an example, when a user calls an 800 number previously assigned to a business, the user""s local exchange routes the call to a special network node, called a Service Switching Point (SSP). The SSP accesses an intelligence layer provided in the network, which includes a database for translating the 800 number received from the SSP into an actual destination number. The SSP receives the destination number from the network intelligence layer, and then proceeds to establish the call connection between the user and the business. The call is then charged to the business having the 800 number.
To provide IN services, network nodes, such as SSPs and intelligence layer databases, must exchange control information for setting-up, monitoring, and disconnecting a communication path (i.e., xe2x80x9ccircuit-relatedxe2x80x9d information), and also exchange other information related to IN services (i.e., xe2x80x9cnon-circuit relatedxe2x80x9d information). Such circuit and non-circuit related information, known as xe2x80x9csignaling,xe2x80x9d is transmitted through a common channel signaling network which is independent of the voice channel. Signaling System No. 7 (SS7) is the internationally recognized protocol governing signaling networks.
An SS7 network has two main components: signaling points, and dedicated signaling links. For an IN, signaling points include SSPs, Signal Transfer Points (STPs), and Service Control Points (SCPs). STPs route and transport signaling messages among signaling points, and thus essentially function as exchanges. As mentioned above, SSPs are special network nodes which process calls, detect requests for IN services, and communicate with the intelligence layer of the network. SCPs are part of the network intelligence layer, and contain the logic and data necessary for executing a requested IN service.
As illustrated in FIG. 1, an SS7 network includes mated pairs of STPs 12-17, SSPs 18-19, and SCPs 20-21 connected by bi-directional links (illustrated in FIG. 1 as dashed lines). By providing mated STPs, a mesh link pattern is created which offers redundancy, and thus reliability even in cases of signaling point failure.
Because each signaling link must be able to divert signaling traffic in emergency situations, and to allow for overhead, SS7 links typically carry only approximately 40% of their maximum capacity. Furthermore, SS7 links are expensive to establish because they are dedicated solely to transporting signaling messages.
Deregulation in the telecommunications field, as well as growth in both wireline and wireless markets, has allowed smaller and other non-traditional service providers to enter the telecommunications market. Some such service providers, however, do not have an established link to an existing SS7 network because of the substantial costs of such links, and therefore are unable to access information contained in SS7 network signaling points, or provide centralized IN services offered by SS7 network operators to their customers. Additionally, as the demand for IN services increases, the increased signaling traffic over SS7 links creates potential overflow problems.
The communication system according to the present invention utilizes an open system protocol, such as the Transmission Control Protocol/Internet Protocol (TCP/IP), to transport IN signaling messages between an SS7 network and a service provider. A gateway/bridge is provided between an SS7 network, which includes intelligent nodes, and an open system network, such as the Internet or a private network which operates under an Internet protocol (hereinafter referred to as xe2x80x9can IP networkxe2x80x9d), thereby allowing service providers to receive and send IN signaling messages via an IP network. By encapsulating SS7 signaling messages into a format suitable for transport via an IP network, communicating via the IP network may serve as an alternative to establishing dedicated SS7 links between a service provider and an SS7 network. Furthermore, for service providers who have an established link to an SS7 network, the gateway/bridge provides a secondary transport mechanism for IN signaling messages.